How to read a tire DOT code and find out how old your tires are

Where to find it

Look on the sidewall for the letters “DOT” followed by a string of letters and numbers, usually near the rim. The full code with the date is required on only one side, so if you see a short code without four digits at the end, check the other sidewall (it may face inward).

What the characters mean

• DOT: the tire meets US Department of Transportation safety standards.
• Next two or three characters: the plant that made the tire.
• Middle characters: size and manufacturer codes.
• Last four digits, often inside an oval: the week and year of manufacture.

Tires made before 2000 use a three-digit code (two for the week, one for the year of the decade). If you find one, the tire is well past its service life.

How old is too old?

Many vehicle and tire makers recommend having tires inspected every year once they pass five years, and replacing them six to ten years after manufacture regardless of tread. Heat, sun and long periods parked speed up aging, so in hot climates lean toward the lower end. Check the spare too.

Also check the date when you buy “new” tires. A tire can sit in a warehouse for a year or more before it reaches you.

Let your phone read it

DOT codes are molded black-on-black and often dusty, which makes them hard to read. Tread AI reads the code from a photo of the sidewall, works out the age for each tire, and adds it to your inspection report.